C. Rossetti

12C16O2 analysis of emission Fourier spectra in the 4.5-μm region: Rovibrational transitions 0v2lv3-0v2l(v3 − 1), v2 = l

Abstract Emission spectra of CO2, vibrationally excited by a dc electric discharge, were recorded under Doppler-limited resolution, using a high-information Fourier transform interferometer, in the spectral range of 4–5 μm. Results concerning 49 vibrational transitions with Δv3 = 1 of 12C16O2 are reported. About 2000 wavenumbers, achieving at least a 10-fold improvement in accuracy over previous measurements for all the “hot” transitions, are given with an absolute uncertainty of the order of 10−4 cm−1 for the best of them. The band centers and the spectroscopic constants for all the vibrational levels involved are reported. They reproduce the experimental wavenumbers with a rms of the order of 2 × 10−5 cm−1 for the best vibrational transitions and 3 × 10−4 cm−1 for most of the others. From weighted simultaneous fits of all the experimental wavenumbers, sets of molecular parameters were computed. Fourty-four parameters allow us to reproduce the 2000 experimental wavenumbers with a rms lower than 9 × 10−5 cm−1.

Experimental rovibrational populations of CO up to ν = 40 from doppler-limited fourier spectra of the sequences Δν = 1, 2 and 3 emitted by a laser type source

Abstract High-resolution emission Fourier spectra have been recorded from a CON 2 HeO 2 mixture excited by dc discharge and cooled by liquid nitrogen. Intensities of all the observed rovibrational lines belonging to sequences Δν = 1, 2 and 3 of 12 C 16 O and 13 C 16 O, and Δν = 1 of 12 C 16 O, have been measured. The data treatment is described. Accurate determination of the rotational distribution and of the vibrational populations of the three isotopic species is performed. The Δν = 2 and 3 vibrational radiative transition probabilities, versus the Δν = 1 ones, are also given, up to ν = 40.

13C16O2, 13C18O2: Emission spectra in the 4.5-μm region

Abstract In this paper the same kind of results are given for 13C16O2,and 13C18O2 as for 12C18O2 [D. Bailly and C. Rossetti, J. Mol. Spectrosc.105, 215–228 (1984)]. Forty seven vibrational bands are analyzed from which spectroscopic constants are computed. These constants reproduce wavenumbers with a RMS of the order of 3 × 10−5 cm−1 for the best measurements. For each species, a set of molecular parameters is given for Σ-Σ transitions.

12C18O2: High-resolution emission spectra in the 4.5-μm region rovibrational transitions 0v′2v3 → 0v′2(v3 − 1), v2 = l

Abstract Emission spectra of gaseous mixtures involving isotopic species of CO 2 excited by a dc discharge were recorded under Doppler-limited resolution, using a high-information Fourier Transform Interferometer, in the region 4–5 μm. In this paper are given the results concerning 34 vibrational transitions (Δ v 3 = 1), for 12 C 18 O 2 . The band centers and the spectroscopic constants for the 39 vibrational levels involved are reported. They reproduce more than 1000 experimental wavenumbers with a RMS of the order of 2 × 10 −5 cm −1 for the best vibrational transition and less than 3 × 10 −4 cm −1 for most of the others. From a weighted simultaneous fit of all the experimental wavenumbers belonging to the Σ-Σ transitions, a set of molecular parameters was computed. A good reproduction of the experimental wavenumbers was obtained for all the vibrational transitions except those involving the level v 3 = 9, our conclusion being that a local vibrational perturbation exists for this level.

Vibrational luminescence of CO2 excited by dc discharge: Rotational and vibrational molecular constants

Abstract High-resolution measurements have been performed on 33 emission bands of the carbon dioxide molecule from 4.2 to 4.7 μm. Accurate values of the vibrational and rotational constants of 39 vibration levels were obtained. Molecular constants were calculated from observed wavenumbers.

12C16O2: Vibrational population distributions in CO2N2, CO2He and CO2N2He dc discharges from high-information emission fourier spectra

Abstract Emission spectra of flowing CO2N2, CO2He and CO2N2He mixtures excited by a dc electric discharge were recorded under Doppler-limited resolution, using a high-information Fourier transform interferometer in the spectral range of 4–5 μm. Nearly 3000 well-isolated rovibrational lines, belonging to 57 vibrational transitions Δυ3 = 1 of 12C 16O2 have been assigned and their intensities have been measured. From these measurements, the rotational temperature and the populations of all the vibrational levels involved have been deduced for the three mixtures studied, showing the influence of the foreign gases. These results are compared to those predicted by the model of Moore and that of Treanor et al.

Vibrational luminescence of N2O excited by dc discharge: Emission lines intensities and populations of rotational-vibrational levels

Abstract A SISAM spectrometer was used for studying the spontaneous emission of a gaseous mixture N 2 ON 2 excited by dc discharge in the 4.7 μm range. Populations of the rotation-vibration levels have been obtained from measurements of line intensities.